Process of desilverizing lead bullion



(No Model.)

w. H. HOWARD PROCESS OF DESILVERIZING LEAD BULLION.

No. 563,769. Patented July 14, 1896.

molten argentiferous lead, forming an UNITED STATES PATENT OFFICE.

\VILLIAM HENRY IIOIVARD, 0F PUEBLO, COLORADO.

PROCESS OF DESILVERIZING LEAD BULLiON.

SPECIFICATION forming part of Letters Patent No. 563,769, dated July 14, 1896. Application filed July 27, 1895. Serial No. 557,317. (No specimens.)

To 0015 whom it may concern.-

l-ie it known that I, \VILLIAM HENRY IIOW- ARI), a citizen of the United States, residing at Pueblo, in the county of Pueblo and State of Colorado, have invented certain new and usef ul Improvements in Desilveriziug Lead Bullion; and I do declare the following to be a full, clear, and exact description of theinvention, such as will enable others skilled in the art to which it'appertains to make and use the same, reference being had to the accompanying drawings, and to the letters of reference marked thereon, which form a part of this specification.

My invention relates to metallurgy, and its object is to facilitate and cheapen the process of treating zinc-silver crusts in the desilverization of lead bullion.

In what is known as Parkess process for effecting this result, zinc is stirred into the alloy or crust, which rises to the surface. This crust is of mushy consistency, and consists of zinc and silver and gold in granular form, saturated with a large excess of lead, only a small portion of which is combined with the alloy, the greater portion being mechanically mixed therewith. To liquate the excess of lead in the crust when skimmed ofi, this alloy is sweated in an iron pot or in a reverberatory or other furnace, additional heat being applied in each case. Inasmuch as the meltingpoint of the mechanically-mixed pure lead is lower than that of the alloy, the former melts and drains out of the crust by gravity. This method, however, removes only a compare. tively small amount of lead, because much of it seems to be entangled in the crust and will not drain out. The crustwhen dry still contains from seventy-five to eighty per cent of lead, which must be handled and treated in the subsequent r'etorting and cupelling processes by which the zinc, the gold, and the silver are extracted from the crust.

My invention relates especially to the treatment of the crust for the purpose of getting it drier; that is to say, freer from lead, the object being to save time, reduce the quantity of material to be handled, and. bring it into better condition for treatment in the retorts. I also aim to dispense with the furnace or kettles for heating the crust, so that the operation can be performed more economically as well as more quickly.

My improvement consists in subjecting the crust to pressure, whereby the unalloyed lead is squeezed out before it has time to cool and harden. Incidentally, the heat... resulting from the pressure may assist in keeping the- By this method I am able to dispense with all additional external heat and effect a great saving in time. Moreover, I get rid of a much greater quantity of lead, so that the resulting bullion is not only considerably reduced in Weight and bulk and therefore easier to be cupelled, but it runs fifty per cent higher in silver.

My improvement can be carried out in various ways.

In the accompanying drawings, Figure 1 shows in section a desilverizing-kettle and a liquating screw-press. Fig. 2 is a plan of the same. Fig. 3 is a modification. Fig. 4: is a sectional elevation of a press arranged to be kept hot by the lead in the kettle. Fig. 5 shows a device for operating such a press by fluid pressure.

The lIOIl kettle A, which holds the melted argentiferous lead B,is of the usual shape and size. Adjacent to this kettle I provide a press, preferably comprising a cylinder 0, supported on a suitable foundation D and having perforations c in its bottom or inthe lower portion of its walls, or both, and containing a piston E. Any desirable means may be adopted for operating the piston, such as a screw F, working in a nut G formed in or attached to a heavy yoke G spanning the cylinder. The screw is provided with arms f, or the like, for turning it. Under the cylinder is placed a trough and terminating over the kettle A. The zinc crust b is removed from the surface of the lead by any suitable means, such as ahand-. skimmer or the skimmerv and sweater patented by me July 25, 1893, No. 502,122. lVhile still hot and mushy it is put into the cylinder and compressed by the piston. The squeezed-out lead drains through the perforations c and runs back into the kettle. The operation can be very quickly performed before the crust has time to get cool. The

lead liquid.

II, inclined toward pressed and dried cake isthen taken outof the cylinder to'be broken up and sent to the retorts.

lifting-rods c at two or'more points; or the press maybemounted on a truck I adapted to be rolled back on an elevated track, as K,

from its'position over the stationarytrough ll, thcbottom of the press bcingmingcd or;

otherwise removable, so, that it can be rclcasethc cake of crust. y

dropped down, as shown in dotted iincs, to;

the heat of tho lead B to kccp'thc crust hot 7 and liquate the unalloyed;leadtherein- The entire press may be suspended from an overhead carrier L, and by suitable mcchanism, such as cable M, it can bicilowcrcd I into the kettle.

\Vhen the operation of'compressing the "alloy is complete, the press ishoisted, run

away from thekcttle, its bottomremoved, and the cake forced out of the cylinder and dropped on thcfloor', where it can be broken upread y for the retorts. r

. \Vhen, convenient, fluidprcssurc, such as steam or compressed air, may be used to effeet the pressing or the hoisting, or'both- Fig; 5' showsone :form of apparatusfor utiliz-' ing fluid pressure for these purposes. The cylindcrN carries a yoke O,'from which is hung the cylinder'O. In the cylinder N is a piston P, whose rod p is attached to and actuatcs the piston E of the press. Hose R lead the fluid pressure to ports above and below the piston I, being controlled by a cock 7. In the upper part of the cylinder N is a piston S, whose rod 8 is hung to the overhead carrier. A hose R leads air or steam into the cylinder above the piston S when the press is to be hoisted.

If desired, the fluid pressure can be applied directly to the surface of the alloy-for instance, by admitting it to the cylinder below the piston E or some other tightly-fitting cover or lid.

It is evident that many other modifications of the apparatus can be devised without dc? parting from the spirit of my invention.

* Having thus described my invention, what 'loejeet the eakefromthe cylinder 1 V a false bottom 0 may be used, provided with I claim, and desire to secure by Letters Pat- 1 i zinc crust to pressure'afterreinoving it from the desilverizing-kettlc, substantially as described. I

2. The process of liquating zinc crusts which consists insubjr'sctingsaid crusts to pressure without the application of, heat, substantially as'described. V I i Theprocess of liquatingfzinccrustsformed in the desilverization of lead bullion,

:1. Asan improvementin Parkcsfs process of desilverizing lead bullion, subjecting the termed in the: desilverizationof lead bullion,

which consists in collecting said crustsadja- 7 cent to the lead in the desilverizing-kettle and there subjecting them toipressure to squeeze out the u nalloyed lead, substantially as described. 7

d. The process of liquating zinc crusts formed in the desilverization of lead bullion, which consists in collecting said crusts, immersing them in the lead'in the desilverizingkettle, and subjecting them to pressure to kettle for the production of zinc crusts from squeeze out theunalloyed lead, substantially as described. 7 r 1 r r I V 5. The combination with a desilverizing-- ing said press toand awayfromsaid'kettle,

substantially as described.

,6.'In' apparatus forithedesilverization of" I lead bullion, the combination with the dcsih verizing-kettle, of a press comprising a cylinder having a perforated bottom, and means for lowering said press into said kettle, and raising it therefrom, substantially as described.

7. In apparatus for the desilverization of lead bullion, the combination with a dcsilverizing-ket-tle, of a press comprising a cylinder having a perforated bottom, m cans for raising and lowering said press, and means for conveying it to and from a point above said kettle, substantially as described.

In testimony whereof I aifix my signal urc in presence of two witnesses.

\VIIJLIAM HEN R'Y IO \VARI).

\Vitnesscs:

E. H. HAMILTON, W. L. BAIN. 

